import { USERS_TYPING } from '../actions/actionsTypes'; const initialState = []; export default function usersTyping(state = initialState, action) { switch (action.type) { case USERS_TYPING.ADD: if (state.findIndex(item => item === action.username) === -1) { return [...state, action.username]; } return state; case USERS_TYPING.REMOVE: return state.filter(item => item !== action.username); case USERS_TYPING.CLEAR: return initialState; default: return state; } }